References
For Schwalbea
Pennell, F.W. 1935. The Scrophulariaceae of eastern temperate North America. Academy of Natural Sciences of Philadelphia Monograph No. 1. Google Scholar
Sorrie, B.A. 2019a. Schwalbea. In Flora of North America Editorial Committee. 2019. Flora of North America north of Mexico. Volume 17, Magnoliophyta: Tetrachondraceae to Orobanchaceae. Oxford Univ. Press, New York, NY. 737 pp. Google Scholar
Ward, D.B. 2012a. New combinations in the Florida flora III. Phytologia 94: 459-485. Google Scholar